(a) Field of the Invention
This invention relates to gas turbine combustor stabilizers and gas turbine combustors equipped with the stabilizers. Especially, it is related to stabilizers that can widen the operation range of gas turbine combustors to ensure stable combustion and reduce damages to be caused by high temperature combustion gas and gas turbine combustors equipped with the stabilizers.
Further, the present invention is related to a method to check combustion conditions in each combustor in which premixed combustion is carried out, as well as it is related to a system that executes this method and a controller of the combustor equipment.
(b) Description of the Prior Arts
In order to carry out stable combustion in a gas turbine combustor, it is very important to hold flames, that is, to stabilize the flames. The use of a stabilizer is very effective to assure such an operation. And there have been some types of such stabilizers as disclosed in Japanese Patent Application Laid-Open No. 115624/1982 which is related to a V-letter shape stabilizer (V gutter) with small wings used to effect sufficient mixing in wake occurring at a downstream side of the V gutter, Japanese Patent Application Laid-Open No. 210721/1989, related to a method to attach stabilizers that have simplified V-letter groove shaped cross sections, respectively, and the U.S. Pat. No. 3,736,746, related to the places to put stabilizers.
Gas turbines need to be operated in a wide output range corresponding to a large change of load. As for a power generation land type gas turbine, it must stand long time continuous operations. The gas turbine combustor stabilizer, therefore, must have performance enough to maintain stable combustion conditions and resistance to deformation and cracks by heat under the wide range of operation conditions. Concretely, the stabilizer must be able to prevent occurrence of unstable combustion such as accidental fire, flash back, combustion oscillation, etc. even when the operation condition changes due to a load change, etc. In addition, since the stabilizer is exposed to high temperature combustion gas on the one hand and exposed to the air and fuel gas flowing into the combustor on the other hand, a maximum stabilizer temperature must be controlled within an allowable one for each component material, as well as it must be structured to suppress excessive thermal stress generation in its local spots. The conventional gas turbine combustor stabilizers cannot meet those requirements yet, however.
Further, it is very important to control the combustion conditions in combustors of a gas turbine to reduce exhaust NOx and key uniform the combustion gas temperatures at the combustor outlets to prevent the turbine blades from being excessive loaded. The combustor combustion condition control techniques have been disclosed, for example, in Japanese Patent Application Laid-Open No. 218535/1985, No. 135942/1986, No. 49136/1986, and No. 29626/1989. Those techniques are roughly classified into controlling of the fuel amount to jet out according to the combustion gas temperature detected at the combustor outlet and controlling of the fuel amount to jet out according to the NOx concentration detected at the combustor outlet.
In addition to those techniques, another technique is introduced, which technique controls the fuel amount to jet out, etc. using an image processing technique from filmed flame images formed in the subject combustor.